The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
Hybrid powertrain architectures include torque-generative devices, including internal combustion engines and electric machines, which transmit torque through a transmission device to a vehicle driveline. Exemplary electro-mechanical transmissions are selectively operative in fixed gear modes and continuously variable modes through actuation of torque-transfer clutches. A fixed gear mode occurs when rotational speed of the transmission output member is a fixed ratio of rotational speed of the input member from the engine, typically due to actuation of one or more torque-transfer clutches. A continuously variable mode occurs when rotational speed of the transmission output member is variable based upon operating speeds of one or more electrical machines. The electrical machines can be connected to the output shaft via actuation of a clutch, or by direct connection. Clutch activation and deactivation is typically effected through a hydraulic circuit, including electrically-actuated hydraulic flow management valves, pressure control solenoids, and pressure monitoring devices controlled by a control module.
It is known for example, to inhibit the utilization of a clutch in order to prevent hydraulic flow from feeding the clutch during conditions in which an associated pressure control solenoid is stuck. Inhibiting the utilization of a clutch results in limited operation of the hybrid powertrain.